Kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during hot-air drying / 中国中药杂志

The present study explored the kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during the hot-air drying process to obtain the optimal process parameters under multiple goals such as drying efficiency and drying quality. The dry basis moisture content and drying rate curves along with the change of drying time of Atractylodis Macrocephalae Rhizoma were investigated at five levels of drying air temperatures(30, 40, 50, 60, and 70 ℃). The relationship between moisture ratio and time in the drying process of Atractylodis Macrocephalae Rhizoma was fitted and verified by Midilli model, Page model, Overhults model, Modified Page model, Logaritmic model, Two terms Exponential model, and Newton model. Meanwhile, the effective diffusion coefficient of moisture(D_(eff)) and activation energy(E_a) in Atractylodis Macrocephalae Rhizoma were calculated under different drying air temperatures. GC-MS was used to determine the volatile components and content changes of the fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures. The dry basis moisture content and drying rate of Atractylodis Macrocephalae Rhizoma were closely related to the temperature of the drying medium, and the moisture of the Atractylodis Macrocephalae Rhizoma decreased with the prolonged drying time. As revealed by the drying rate curve, the drying rate increased with the increase in hot air temperature, and the migration of moisture was accelerated. The comparison of the correlation coefficient(R~2), chi-square(χ~2), and root mean standard error(RMSE) of each model indicated that the parameter average of the Midilli model had the highest degree of fit, with R~2=0.999 2, χ~2=8.78×10~(-5), and RMSE=8.20×10~(-3). Besides, the D_(eff) at 30-70 ℃ was in the range of 1.04×10~(-9)-6.28×10~(-9) m~2·s~(-1), and E_a was 37.47 kJ·mol~(-1). The volatile components of fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures were determined by GC-MS, and 18, 18, 18, 17, 17, and 18 compounds were identified respectively, which accounted for more than 84.76% of the volatile components. In conclusion, the hot-air drying of Atractylodis Macrocephalae Rhizoma can be model-fitted and verified and the variation law of the moisture and volatile components of Atractylodis Macrocephalae Rhizoma with temperature is obtained. This study is expected to provide new ideas for exploring the drying characteristics and quality of aromatic Chinese medicine.

Effect of Different Hot Air Drying Methods on Chemical Constituents of Trichosanthis Fructus / 中国实验方剂学杂志

Objective:To compare the effects of different drying methods on the chemical constituents of Trichosanthis Fructus. Method:Trichosanthis Fructus was dried by means of air drying， sun drying， hot air drying （40， 60， 80 ℃） and variable temperature drying （50-80， 80-50 ℃）. The contents of nucleosides and flavonoids in Trichosanthis Fructus peels and seeds treated by different methods were compared by high performance liquid chromatography （HPLC）， mobile phase was acetonitrile-0.2% acetic acid aqueous solution （3∶7） （A）-acetonitrile （B） for gradient elution （0-15 min， 97-95%B； 15-30 min， 95%-90%B； 30-35 min， 90%-87%B； 35-40 min， 87%-86.5%B； 40-48 min， 86.5%-97%B； 48-50 min， 97%B）， the detection wavelength was 260 nm， and the flow rate was 0.4 mL·min^-1. Gas chromatography-ion mobility spectrometry （GC-IMS） was used to compare the changes of volatile components in the samples treated by different treatments. The volatile components were incubated on a SE-54 capillary column （0.32 mm×30 m， 0.25 μm） at 80 ℃ and 500 r·min^-1 for 15 min， the injection temperature was 85 ℃， the injection volume was 400 μL， the analysis time was 35 min， carrier gas was high purity nitrogen， the flow rate of carrier gas was 2.0 mL·min^-1， the flow rate of drift gas was 150 mL·min^-1， and the temperature of IMS detector was 45 ℃. Result:The contents of uridine， adenosine and adenine were higher after hot air drying at >50 ℃. Low temperature drying was conducive to maintaining the stability of cytidine， cytosine， rutin， luteolin and 2ʹ-deoxyadenosine. GC-IMS technology could realize the analysis and identification of Trichosanthis Fructus samples after different treatments. There were more volatile components after hot air drying at 80 ℃ and variable temperature drying. Conclusion:Hot air drying at 40 ℃ and 60 ℃ can retain nucleosides and flavonoids， and the volatile components are similar to those in traditional drying methods， which has the advantages of high efficient， controllable and suitable for industrial production.

Effect of relative humidity on drying characteristic and quality of Panacis Quinquefolii Radix / 中草药

Objective: Taking Panacis Quinquefolii Radix (PQR) as study object, the drying characteristic and quality was investigated under constant relative humidity (RH) and step-down RH drying method in order to provide foundation for improving drying efficient and quality of PQR. Methods: At drying temperature 55 ℃, the effect of constant RH (20%, 30%, and 40%), step-down RH, when RH 40% was kept for 1, 5, and 9 h and then decreased to 20%, and continuously dehumidification drying conditions on drying characteristic, moisture effective diffusion coefficient, rehydration ratio, shrinkage ratio, total ginsenoside content and microstructure were investigated. Results: With constant RH drying condition, the lower the RH was, the higher the drying rate was. When RH was 20%, the drying time was shortened by 6.8% compared with RH of 40%. With step-down RH drying condition, when RH 40% was held for 5 h and then decreased to 20%, the drying time was shortened by 3.4% compared with dehumidification drying method. Also, a transient increasing drying rate phase was appeared. Moisture effective diffusion coefficient ranged from 1.49 × 10-10 to 2.50 × 10-10 m2/s. Rehydration ratio mainly depended on the damage degree of the PQR cellular structure and the moisture content before rehydrating. Additionally, the rehydration ratio and shrinkage ratio increased with the increase of RH. High RH was benefit for reserving and transferring of ginsenoside content. The microstructure results showed that under continuous dehumidification drying process, the PQR surface was crusted so that the drying time was prolonged and rehydration ratio was decreased. On the other hand, step-down RH drying method was benefit for porous structure formation, which was helpful for shortening drying time and improving rehydration ratio. When RH 40% was kept for 5 h and then decreased to 20%, the comprehensive score of this drying condition achieved its maximum value as (0.61 ± 0.01). Such drying condition was regarded as the best drying process with the rehydration ratio, shrinkage ratio and total ginsenoside content of 2.23 ± 0.12, 0.26 ± 0.06, and (5.01 ± 0.04)%, respectively. Conclusion: Step-down RH drying method can improve PQR drying efficient and quality and such conclusion provided theoretical foundation and technical support for how to adjust RH during hot air drying of PQR.

Simulation and experiment of temperature uniformity of Erzhi Pills during hot air drying process / 中草药

Objective: To explore the law of temperature change in hot air drying process, and provide a theoretical basis for improving the drying efficiency and uniformity of Erzhi Pills (EP). Methods: Heat and mass transfer models were established to simulate the temperature distribution of the drying process of EP with no hole bottom and screen hole bottom based on COMSOL Multiphysics. The drying process of EP layer at 60, 80 and 100 ℃ was studied. The effective water diffusion coefficient (Deff) of EP layer was calculated by Fick’s second law plate model. A probe temperature sensor was used to monitor the temperature changes of the intermediate surface and interior of EP layer during the drying process to verify the drying model. Results: The surface and internal temperature of EP layer showed a trend of first sharp rise and then slow rise in the drying process of different hot air temperature. The inner temperature range of the drying model with no hole bottom and screen hole bottom was 55.3-56.0 ℃ and 57.5-57.7 ℃ respectively. The uniformity of drying temperature of EP can be improved by using drying plate with screen hole. The Deff range of the two model experiments were 0.76 × 10-7-2.82 × 10-7 m2/s and 1.15 × 10-7-3.94 × 10-7 m2/s, respectively. The experimental results showed that the model could well reflect the temperature variation of EP layer drying process within a certain drying temperature range. Conclusion: The change of drying temperature was directly reflected through the reliable hot air drying model of EP layer. The study provides reference for the optimization of EP drying process.

Influence of different drying techniques on drying parameters of mango

Abstract This research inspected the effects of freeze, microwave (120 and 350 W) and hot air (60, 70 and 80 °C) drying techniques on the color, drying characteristics, antioxidant capacity and total phenolic content of mango slices. Midilli et al., Two-term and Page models which exemplify drying characteristics are superior than alternative models. All of the color values (a, b, L, C, α and ΔE) were altered notably based on the used drying technique and colors nearest to the fresh sample were attained with freeze drying. In comparison to the fresh sample, the dried samples showed a decrease of 18.4-54.6% in antioxidant capacity. The total phenolic content value was notably highest one for the microwave dried sample at 350 W and the lowest one for a hot air dried sample at 80 °C (P<0.05). This research showed that microwave drying at 350 W is able to yield high-quality mango slices with the extra advantage of shortened drying time in relation to hot air and freeze drying.

Effects of Different Drying Technologies and Slicing on the Quality of Tetrastigma hemsleyanum by Multi-in-dexes Evaluation / 中国药房

OBJECTIVE:To study the effects of different drying technologies and slicing on the quality of Tetrastigma hemsley-anum,and optimize the drying methods for T. hemsleyanum. METHODS:2 treatment methods(slicing and no slicing)and 5 dry-ing methods(drying in the shade,drying in the sunlight,hot-air drying,microwave drying and freeze drying)were respectively ad-opted for the T. hemsleyanum root. After drying for 3.5-213.0 h,using the total flavonoids,total polyphenols,polysaccharides andβ-sitosterol as indexes,effects of different drying technologies on the quality of T. hemsleyanum were comparatively analyzed. RE-SULTS:Compared with no slicing,sliced T. hemsleyanum can shorten the drying time and reduce the loss of active ingredients. In the 5 drying methods,freeze drying was the best for keeping the active ingredients in T. hemsleyanum. After drying,the contents of total flavonoids,polysaccharides,total polyphenols and β-sitosterol were 18.5 mg/g,92.7 mg/g,9.19 mg/g and 0.344 mg/g respec-tively,followed by microwave drying,hot-air drying,drying in the shade and drying in the sunlight. The contents of active ingredi-ents had statistical significance by each drying methods (P<0.05 or P<0.01). CONCLUSIONS:Different drying technologies have obvious effects on the quality of T. hemsleyanum. Slicing and hot-air drying at 60 ℃ were suggested as suitable method for T. hemsleyanum in terms of cost,content of active ingredients and practicability.

Comparison of sulfur fumigation processing and direct hot air heating technology on puerarin contents and efficacy of Puerariae Thomsonii Radix / 中国中药杂志

In order to compare the effect of sulfur fumigation processing and direct hot air heating technology on puerarin contents and efficacy of Puerariae Thomsonii Radix, the fresh roots of Pueraria thomsonii were cut into small pieces and prepared into direct sunshine drying samples, direct hot air drying samples, and sulfur fumigation-hot air drying samples. Moisture contents of the samples were then determined. The puerarin contents of different samples were compared by HPLC method. Moreover, the models of drunkenness mice were established, and then with superoxide dismutase (SOD) content as the index, aqueous decoction extracts of Puerariae Thomsonii Radix samples with sulfur fumigation processing and non-sulfur fumigation processing methods were administrated by ig; the effects of sulfur fumigation on contents of SOD in mice liver and serum were determined, and the sulfur fumigation samples and non-sulfur fumigation samples were investigated for moth and mildew under different packaging and storage conditions. Results showed that the sulfur fumigation samples significantly changed the puerarin content from Puerariae Thomsonii Radix. The content of puerarin was decreased gradually when increasing the times of sulfur fumigation and amount of sulfur. SOD content in drunken mice liver and serum was significantly decreased when increasing the times of sulfur fumigation, showing significant difference with both direct sunshine drying group and direct hot air drying group. Moth and mildew were not found in the sulfur fumigation samples and direct hot air drying samples whose moisture contents were lower than the limit in Pharmacopoeia. Research showed that sulfur fumigation can significantly reduce the content of main active ingredients and reduce the efficacy of Puerariae Thomsonii Radix, indicating that the quality of Puerariae Thomsonii Radix was significantly decreased after sulfur fumigation. However, the contents of the main active ingredients, efficacy and storage results of the direct hot air drying samples were similar to those in direct sunshine drying samples, so the hot air drying process was a nice drying technology which could be promoted for use.

Drying Kinetics of Gum Karaya (Sterculia urens) Using Convective Air Dryer.

The present study was aimed to investigate the drying kinetics of gum karaya (S. urens). Three grades of gum (I, II, III) were dried using a cabinet-type convective dryer. Particle size equivalent to US Sieve size-6 and air temperatures of 50, 60 and 70°C were used for the drying experiments. The experimental drying data was fitted to Page’s model to predict the drying kinetics. Investigations with constant air velocity revealed that for grade- I gum, drying rate constant (k) varied between 0.2744-0.3742 (h-1), for grade-II gum between 0.3208-0.4439 (h-1) and for grade-III gum between 0.4098-0.4639 (h-1). The dimensionless number (n) was always more than 1 and minimum value of the Coefficient of determination (R2) was 0.967. Increase in air temperature enhanced drying process and drying rate. For each particular temperature, the values of drying rate constant were minimum for grade-I, maximum for grade-III and intermediate for grade-II gum.